Antirolling device for ships



Dec. 3, 1940.

J. V. GILIBERTY ANTIROLLING DEVICE FOR SHIPS Filed Feb. 11, 1939 3Sheets-Sheet l INVENTOR James V. Gili bari- Y ads (10% 2;

ATTORNEY Dec. 3, 1940. J. v. GILIBERTY ANTIROLLING DEVICE FOR SHIPSFiled Feb. 11, 1939 3 Sheets-Sheet 2 INVENTOR JamesV. Giliberi ATTORNEYDec. 3, 1940- J. v. GILIBERTY ANTIROLLING DEVICE FOR SHIPS Filed Feb.11, 1939 3 Sheets-Sheet 3 INVENTOR JAMESVGILIBERTY BY 3 ATTORNEYPatented Dec. 3, 1940 UNITED STATES PATENT OFFICE 2,223,562 ANTIROLLINGDEVICE FOR SHIPS James V. Giliberty, Hempstead, N. Y. ApplicationFebruary 11, 1939, Serial No. 255,843

-2 Claims.

I'his invention relates to antirolling devices for ships of the type inwhich stabilizing fins projecting laterally from the side of the shipare turned about an axis perpendicular to the longitudinal axis of theship in such a direction as to oppose the rolling movements of the ship.

When such fins are located a substantial distance either forward or aftof the ships center of gravity, they oppose the pitching movements ofthe ship as well as its rolling movements.

It has been proposed to change the angular positions of such fins byhydraulic or mechanical means located inside the ship and controlled byi a gyroscope. While such means are Very efiicient,

' pitching movements of they are expensive to construct. They are alsoquite complicated and are therefore more susceptible to mechanicalderangement.

The principal object of the present invention, therefore, is theprovision of simple, inexpensive means for automatically changing theangle of attack of such fins in such a direction that the flow of waterpast the fins due to the ships longitudinal movement through the waterexerts pressure on the fins to oppose the rolling-and/or the ship.

Where gyroscopic control is used the angular movement of the shiprelatively to a horizontal plane is employed to change the position ofthe stabilizing fins. According'to the present invention the angularmovement of the ship relatively to the water is employed for thatpurpose, thereby greatly simplifying the construction and operation ofthe stabilizer.

Broadly speaking, the invention involves controlling the angularposition of the fin by means of a plate, which will hereafter be calledthe control plate, mounted on the outside of the ship in such a way thatit can move upwardly relatively to the adjacent part of the ship as suchpart moves downwardly through the water as the result of the upwardpressureof the water on such plate.

On a large ship the lateral angular movement of its sides through thewater due to rolling may be a considerable number of feet. The movementof the control plate relatively to the ships side, may not be in excessof a few inches. As a result the total movement of the plate isdownward, although there is a simultaneous movement ofv the plateupwardly with respect to the adjacent part of the ships side. Itfollows, therefore, when reference is made to such plate movingupwardly, that it would be more accurate to say that it does not movedownwardly as rapidly or asfar as it would had it been rigidly securedto the ships side. However, for convenience, movements of such plate andthe other parts of the stabilizer will hereafter be referred to asupward or downward when such parts move up 5 ward or downward withrespect to the adjacent side of the ship.

The control plate mentioned above is used to control the direction inwhich the fins are inclined with respect to the horizontal and also themagnitude of their angle of attack. It may control the angular positionof the fins by controlling the application of motive power from theships power plant to the stabilizing fins. A simpler method is toconnect each plate to an adjacent fin in such a way that the forceexerted against the plate, resulting from the rolling and/ or pitchingof the ship, is transferred to the stabilizing fin in such a day thatthe angle of attack of the latter is changed in sucha direction that thepressure of the water on the fin opposes the rolling and/ or pitchingmovement of the ship. In either case, the rolling and/or pitchingmovement of the ship acting through the control plate controls the angleof attack of the fin both as to direction and also as to magnitude withrespect to the fore and aft flow of water.

Where the stabilizing fin is turned as'the result of a direct connectionbetween the stabilizing fin and the control plate, the stabilizer unitsare self-contained and positive in action. This results in greatlysimplifying the construction and operation of the stabilizer and therebycontributes to greater reliability.

Another simple, and the preferred, method is to use the control plate tothrow into operation fin deflecting means which derive their deflectingforce from the forward motion of the ship. It is advantageous to use thepressure created by the forward movement of the ship through the waterto turn the stabilizing fin for the reason that, per unit of area, it isso much greater than the pressure due to rolling movement. For example,one large ship has a maximum circumferential rolling movement of around1.8 feet per second. On the other hand, the same ship at full speedtravels at 30 knots or more, which is equivalent to a speed of over 50feet per second.

With either of the last two mentioned arrangements, the angle of attackof the stabilizing fins is controlled by the controlplates independentof anyv motive power for said control; other than the forces resultingfrom the ships angular movement and. the ships forward velocity.

j thefin to produce allel to, or coincident with, that of the stabiliz--ing fin, or second, about an axis at right angles stabilizing finand tothe longitudinal axis Ofthe to the axis of rotation of the usuallyparallel ship.

In all cases, the normal or neutral "position of the control plate issuch that its plane isparallel to the direction of fore or aftmovementof the ship. Ifthe control plate is mounted so as ,to turn aboutan axis which. is also parallel to such direction of movement, its planeis always parallel to the fore and aft water fiow. ,If, on the otherhand, the control plate is arranged to turn about an axis parallel to,or coincident with, that of the stabilizing fin, its plane does notmaintain this parallelism. The extent. to which parallelism is departedfrom for any given lateral movement of the-center of pressure of the,control, plate depends on how far suchcenter of pressure is from theaxis about which such plate swings.

Any angular velocity of roll produces a strong reaction on thecontrolplate. This reaction is utilized to actuate the stabilizing fin, throughgears, links, levers, or through the medium of a pilot rudder attachedto the stabilizing, fin. The connection provided between ,thestabilizingfin and the control plate is such that movement, of,thecontrol plate causes the leading edge of the .stabilizingfin to movein the same direction as the control plate, thereby producing a force onthe hull tending to checktherolling motion of the ship.

As the stabilizing fin moves edgewise through the water as. theresult ofthe forward movement of the ship,

,of the-'shipdepends on how well the fin is balanced. The nearer theturning axis is to the balance pointthe less the force required.

If the fin were perfectly balanced hydrodynamically, the force requiredto turn it would be only that required to overcome the friction of thesupport. In practice, perfect balance is impossible as the position ofthe turning axis of perfect balance varies with the speed of the ship;the higher the speed the nearer such axis would have tobe to the leadingedge of thefin. The important point is that two forces have to beovercome to cause the leading both reduced by mounting the fin on edgeof the fin to incline upwardly as the fin 'duetofthe rolling motion ofthe ship and that due to the "turning movement required to give thefin acorrect angle of attack. Both these forces are in the same direction andthey are the balanced rudder principle. To prevent the fore and [aftflow of water turning the fin broadside on or completely Jaround through180, the fin should be mounted with its axis of rotation forward ofthebalance point of the fin at the maximum speed of-the ship.

the force required to turn the fin out of parallelism with the directionof movement the force On the other hand, it is desirable that thecontrol plate should be not only wholly unbalanced but also mounted sothat, as it moves upwardly as the adjacent side of the ship movesdownwardly, it does not move markedly out of parallelism with the foreand aft flow of water. Any marked angular movement of the control plateaway from parallelism with the fore .and aft flow means an unnecessarychecking of the forward movement of the ship and ,usually also exertinga thrust laterally inopposition to that produced by the stabilizing finwhen turned so as to oppose the rolling motion of the ship. A close"approach to constant parallelism is obtained by mounting the, controlplate on the end of a long .arm so that over a considerable range ofvertical or lateral movements there is only a slight change in the angleof attack with respect to the fore and aft flow of water, or by mountingthe control plate so that its axis of rotation is ap' proximatelyparallel to the longitudinal axis of theship. v

A fin freely rotatably mounted on a shaft proaxis of rotation forward ofthe balance point of the fin would be deflected by the rolling action ofthe ship in such a direction that such fin would accentuate the rolling,i. e. give it an angle of attack in the wrong direction. In order toprevent this, it becomes necessary by auxiliary means to a'pply'forceswhich not only overcome the above. mentioned inherenttendency to producethe wrongangle of attack, but also to produce a deflection of the fin inthe tion, so that the desired angle of attack in the right direction toresist roll is. produced.

Various embodiments of myinvention are illustrated, by Way of example,in the accompanying drawings, wherein:

Fig. 1 is a plan view'of my stabilizer Fig. 2 is asection on the line2-2 of Fig. 1;

Fig. 3-is a diagrammatic sectional view of the stabilizer of Fig. 1,showing the position of the parts as the stabilizer is pushed upwardlythrough the water by the rolling of the ship;

Fig.4 is a view similar to Fig. 3 showing the position of the parts asthe stabilizer is moved downwardly through the water by the return rollof theship;

Fig. 5 is a side'elevation of a ship equipped with my stabilizers inplace of the usual bilge keels;

Fig. 6 is a front elevation Fig. 7 is a perspective view of the form ofstabilizer shown in Fig. 1; and

Figs. 8 to 12, inclusive, are perspective views of modified forms of mystabilizer.

In the preferred form Figs. 1 to 7, inclusive, l5 represents thestabiliz-' ing fin, l 6 the control plate, and pivotally connected toboth the stabilizing fin and control plate.

The stabilizer as a whole is rotatably mounted on a stub shaft 20 havinga. flange 2| at one end the preferred form of of the same; I

jecting laterally outwards from the hull with its opposite direcofstabilizer shown in v I! a pilot rudder by which it may be secured tothe side 22 of the 25 the mid-portion of which is attached to the frontend of the fin by a screw 26, while the ends of the spring are coupledtogether by tension adjusting screws 21 and 28. On the stub shaft 20 ismounted a cam 30 attached to a set-screw 3|. This cam has fiat sidesagainst which the two halves of the spring press. As the fin turnseither way from the position shown in .Fig. 2, the two halves of thespring are forced apart.

The construction shown has the advantage that the fin can be turned vsothat it can operate as a stabilizer when the ship is going astern aswell as when it is going forward.

Rotatably mounted on the shaft 20 between the flange 2| and the cam 30is an arm 35, slotted at 35 (Fig. 7) at its rear end to slidably receiveone edge of the control plate H5. The control plate I5 is coupled to thefin l5 by a pilot rudder H. The latter is pivotally connected to the finI5 by lugs 31, 38 and to the control plate l6 by a lug 39 and a pin 40.

When the ship rolls, the fin [5, control plate l5 and pilot rudder I!assume the positions shown in Figs. 3 and 4 alternately. When the shiprolls in the direction of the arrow A (Fig. 3) so as to push thestabilizer .as a whole upwards through the water, the control plate ispushed downwardly in the direction of the arrow B. As shown, thisdownward movement of the control plate has moved the rear edge of thepilot rudder downwardly into the path of movement of the water flowinglongitudinally of the ship in the direction of the arrow C, due to itsforward movement. The pressure on the pilot rudder so produced hasrestricted the downward movement of the control plate and at the sametime pushed the rear part of the fin l5 upwardly. This last mentionedeffect is the important one, as it is the one which results in thedeflecting of the stabilizer fin in such a direction as to counteractthe rolling movement of the ship. When the return roll takes place, themovements are all reversed, as indicated in Fig. 4.

It may be said that the control plate is floating, that is, it hascomplete freedom of movement in either direction from its centralposition. It follows then that a lateral movement of the fin unit whichis equivalent to the movement of the ship in the direction of arrow Aresults in the movement of the control plate in the direction of arrowB. This relatively opposite movement is caused by the resistance offeredby said plate to lateral movement through the water. Since the controlplate is pivotally connected to the pilot rudder it follows that themovement of the control plate causes the pilot rudder to assume an angleof attack relative to the normal streamlines. Through the medium of thepivot connections 31 and 38 (Fig.1) the resultant force on the pilotrudder due to forward ship velocity then acts to give the stabilizingfin proper, its correct angle of attack. This last mentioned effect isthe important one, as it is the one which results in the deflecting ofthe stabilizer fin in such a direction as I to counteract the rollingmovement of the ship. It will be noted that the pilot rudder isbalanced, i. e. the axis about which it turns is well aft of its leadingedge. As a result it is readily turned by the control plate.

It will be noted that the magnitude of the angle of attack of thestabilizing fin proper is also automatically controlled. When a ship isin a calm sea there is no angular velocity and therefore the stabilizingfin, pilot rudder, and control plate assume their neutral or centralmovement.

position. A slight angular velocity resulting ment of the control platewith a corresponding slight movement of the pilot rudder and stabilizingfin. A large angular velocity resulting from a heavy seaway will cause acorresponding greater movement of the control plate, with a consequentgreater movement of the pilot rudder and stabilizing fin. It followsthen that the corrective moment is automatically controlled, and itsmagnitude is proportional to the angular velocity.

It will be further noted that the action of the fins is such that theyproduce a force in a direction opposite to that in which the stabilizingunit as a whole is oscillating. Therefore, the location of said fins ona ship may be such that they can produce forces to oppose rolling and orpitching.

In a mixed sea where intermittent rolling and pitching exists, thestabilizing fins herein described automatically adjust themselves tothose conditions. The fins respond immediately to any roll or sequencesuch roll or pitch may be or regardless of what combination of roll orpitch may exist.

It is possible to do without a pilot rudder, and Figs. 10, 11 and 12show three forms of construction in which it' is not used. Further, itis not essential that the control plate swing about an axisperpendicular to the ships side. The

control plate may be mounted so as to turn about a horizontal axisparallel to the ships side, as shown in Figs. 8, 9, 11 and 12. Thesemodifications are illustrated to show in what diverse ways the generalprinciples of my invention may be carried into practice.

In the form shown in Fig. 8, the stabilizer fin 50 is mounted to turnabout a shaft (not shown) projecting outwardly from the ships side.Journaled on this shaft and rigidly secured to the fin 55 is a sleeve 51carrying a bevel gear 52. The control plate 53 is rigidly mounted on ashaft 54, journaled in bearings 55 and 55 secured to the ships side.Non-rotatably secured ,to the forward end of the shaft 54 is a bevelpinion 51 inmesh with the bevel gear 52. If the stabilizer is pusheddownwardly through the water by the rolling of the ship, wardly, turningthe shaft 54 and thereby turning the fin 59 so that the water flowinglongitudinally along the ships side strikes the under side of the finand produces an upward thrust on the stabilizer which counteracts therolling On the return roll the control plate swings downwardly andpresents the top surface of the fin to the longitudinal flow of water.By reason of the fact that the control plate is wholly unbalanced andthe stabilizer fin is largely balanced, a comparatively small upwardforce on the control plate will produce a very much greater upward forceon the fin 50, and vice versa.

If desired, the turning of the stabilizing fin 50 may be aided, asshown, by a pilot rudder 6U pivotally mounted at BI and 62 in a recessin the rear edge of the fin. This rudder has an arm 63, slotted at 64for the reception of a pin 65 extending from the outer margin of thecontrol plate 53. This pilot rudder 60, although somewhat smaller, actsin the same way as the pilot rudder I! in the form of construction shownin Figs. 1, 2 and 7.

The form of stabilizer shown in Fig. 9 is simithe control plate swingsup;

from a moderate sea will cause a slight movepitch movement regardless ofwhat lar to that of Fig. 8 except that the fin 70 is turned by thecontrol plate 1| solely through the intermediary of the pilot rudder 12.In this case, therefore, the pilot rudder is a necessity, not merely anoptional accessory, as in theform shown inFig. 6. The stub shaft 68andspring 69 in this stabilizer is similar to the corresponding parts ofFig. 1.

Figs. 8, 9 and 10 show various forms of stabilizer in which no pilotrudder is used. In Fig. 10 the stabilizer fin is rotatablymounted on ashaft 16. The control plate 71 is rotatably mounted on a stub shaft 18,so that it swings about an axis parallel to. but spaced apart from thatabout which the fin 15 turns. To cause the rear part of the fin 15 tomove downwardly while the control plate moves upwardly and vice versa,the control plate is provided with a forwardly extending arm 79, slottedat 80 for the reception of a pin 8| projecting from the inner edge ofthe fin I5.

In Fig. 11 the control plate 85 is hingedly connected to the ships side.The fin 86 has a forwardly extending arm 81 slotted at 88 to receive apin 89 projecting from the outer edge of the plate 85.

The stabilizer of Fig. 12 comprises a fin 96 rotatably mounted on ashaft 91 and provided with leaf springs 94 which cooperates with a fiatsided cam 95 in exactly the same manner as the spring and cam of theform shown in Figs. 1, 2 and 7. The diiference in this case, however,being that said springs, cam and adjusting screws 93 are placed insidethe hull, and secured thereto. Extending rearwardly from the inner partof the fin 96 is a shaft 98 on whicha control plate 99 is pivotallymounted. Leaf springs I09 attached to the fin and extending rearwardly,one each side of the controlplate, serve to yieldingly hold the latterin substantially the same plane as the fin, until rolling or pitchingcommences.

The forward edge of the plate 99 is enlarged at its outer end so as toprovide a surface HH having area sufiicient to offer considerableresistance to the longitudinal flow of water along the ships side. Inthe beginning of a downward roll, the control plate 99 is deflectedupwardly while fin 96 is yieldingly held neutral by means of the springs94. Having moved upwardly, the force due to forward ship motion actingon the surface of NH, causes the trailing edge of fin 96 to movedownwardly, thus causing it to be in the correct position to oppose therolling movement.

In the preferred form of stabilizer shown in Fig. 1, the cam 39 and leafspring 25 is shown outside the hull. It is to be understood that thearrangement of the cam and spring inside the hull as shown in Fig. 12,can also be applied to Figs. 1, 7 and 9. This arrangement has theadvantage in that it enables the fin to be set to its neutral positionat any point along the hull. Thus, if a fin is placed at a point wherethe streamlines are out of parallelism with the lonhind its trailingedge to produce gitudinal axis ,ofthe ship dueto eddy currents or to theWave making eifect of the ships hull, adjustments of the fin to suitthose conditions can easily be made. Having the cam and spring on theinside of the hull also has the advantage in that the spring tension canbe adjusted While the ship is underway.

What is claimed is:'

1. An'antirolling device for water-borne ships comprising a stabilizingfin having leading and trailing edges pivotally attached to the side ofthe ship, the axis of said pivot being substantially perpendicular tothe axis about which the ship rolls and also at a substantial angle tothe vertical central plane of the ship, said .fin being mounted on itspivot so that said pivot is a substantial distance ahead of thegeometrical center of said finand a substantial distance bea balancedrudder action, a control plate pivotally mounted on the side of the shipto turn about an axis fixed with respect to the ship, the axis of thepivot of saidplate being outside the body of but in'the same plane assaid plate so that the latter is unbalanced, the last-mentioned axisalso lying in the plane which includes the rolling axis of the ship andthat part of the side of the ship to which the control plate is attachedto permit the latter to be moved by the water with respect to the shipwith rolling movements of the ship, and means interconnecting thecontrol plate and fin for turning the stabilizingfin so constructedandarranged that the trailing edge of the fin moves about the axis of thefin in the same direction as that in which the adjacent side of the shipis moving as the result of such rolling movement.

2. .An antirolling device for water-borne ships comprising'a stabilizingfin having leading and trailing portions pivotally attached to the sideof the ship, the axis of said'pivot being substantially perpendicular tothe axis about which the ship rolls and also" at a substantial angle tothe vertical central plane of the ship, said fin being mounted onitspivot so that said pivot is a substantial distance ahead of thegeometrical center of said fin and a substantial distance behind itstrailing edge to produce a balanced rudder action, a control platelocated to the rear of said fin, said control plate having leading andtrailing portions, a supporting arm connected to said plate andpivotally connected to the side of the ship at the same point as saidfin but movable independently of the latter, a pilot rudder havingleading and trailing portions, located between the leading portion ofthe control plate and the trailing portion of the fin and having itsleading portion connected to the trailing portion of the fin and itstrailing portion connected to the leading portion of the control platewhereby movement of the control plate resulting from lateral pressure ofthe water due to rolling moves both the pilot rudder and stabilizingfin.

- JAMES v. GILIBERTY.

